Lubricating composition



Patented July 29, 194i LUBRIYCATING COMPOSITION Louis A. Mikeska, Westiield, and Eugene liieber,

Linden, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application October 19,1938,

sci-a1 No. 235,771;

3 Claims. (Cl. 252-46) This invention deals with lubricating composl-1 tions. More specifically, it relates to the use in such compositions of small amounts of soluble organic xanthogen tetrasulfldes which are believed to possess a structure corresponding to the following formula:

where Rand R. represent alkyl, cyclic, or-cycloalkyl organic groups.

These compounds are condensation products which may be obtained in high yields according to the following reactions:

. Z3 ROH+CS:+KOH R-0-C +1110 Potassium xanthate Xsnthogen tetrasulflde An example in the preparation of such a material (ethyl xanthogen tetrasulfide) is as follows:

Potassium hydroxide is dissolved in absolute a1coho1'(fair excess over that required for reaction) and the required amount of carbon disulflde is added with cooling and mechanical agitation. Potassium xanthate precipitates out. The amount of xanthate is further increased by the addition of ether. excess alcohol being saturated with xanthate could be used again, avoiding the use of ether as a precipitant.) The solid product is recovered by filtration and dried.

The potassium xanthate is suspended in benzene (other inert solvents such as light naphtha could be used), stirred and a benzene solution of sulfur monochloride added with cooling. After the sulfur chloride has been added, the reaction mixture is refluxed for 2 hours to complete the condensation, and then poured into water. The benzene layer is removed and dried. After stripping off the benzene, the xanthogen tetrasulflde remains as a residue.

The overall yield averages around 86.7%.

These xanthogen tetrasulfldes possess such un- (In large production, the

and corrosion inhibiting properties. They likewise .exhibit exceptionally potentextreme pressure lubricating properties. Although they are sulfur compounds (ethyl xanthogen tetrasulfide contains about 63% S), they are light colored, oil soluble compounds, possessing a faint pleasant odor, and thus impart no objectionable characteristics to the mineral or other oil base stockin which they are blended.

'I'hese compounds are also compatible with soap, fatty oils and other ingredients normally employed in soluble oils, cutting oils, greases, motor oils, compounded, and industrial lubricants, without causing precipitation. or settling out of sulfur or sulfur compounds.

In the extreme pressure lubricating art the common practice is to add to the lubricating 'oil a sulfurized mineral or fatty 'oil. These com- .pounds are generally dark colored, odorous materials, poor in combined sulfur. Alkyl sulfides and polysulfides have been proposed for this purpose but their pungent and sickening odor markedly limits their uses in this direction. Xanthogen disulfldes, prepared by the oxidation of xanthic salts show relatively poor load carryirig properties, a 5% blend failing on the S. A. E

machine at 200 lbs. load. Although ethyl xanusual characteristics as to impart to lubricating and other oils, new and unexpected properties. For example, they possess excellent antioxidant thogen'trisulfide shows fair load carrying properties, it tends to settle out free sulfur on standing, and is therefore excluded from use to some extent because of its instability. An improved composition can be obtained by chilling the trisulflde or its solutions and filtering to remove the separated material.

However, the xanthogen tetrasulfides (e. g. ethyl xanthogen tetrasulflde) such as'those embodied in the present invention, give excellent results as extreme pressure blending agents. When used alone in mineral lubricating oil, 3% of this material will carry the full load (580 lbs.) on the S. A. E. machine at 1000 R. P. M., and in addition, it meets the requirements of the Packard Stability Test. This test involves the heating of the blend in an oven at 200 F. for 64 hrs. and running the thus-treated oil on the S. A. E. machine at 1000 R. P. M. and 83.6 lbs/sec. loading rate, the rubbing ratio being 14.6:1. The blend must carry a full load of 550 lbs. scale pull.

Blends containing these xanthogen tetrasulxanthate salt prior to condensation. Since these products pick up some of the mercaptan odor which is dimcult to remove, they are not as desirable as the corresponding alcohol derivatives.

One exceptionally wide use for the compositions which are the subject of this invention, is in the field of cutting oils. Here a high E. P. eflect is desired without any detrimental odor or discoloration oi! the base stock, so as to give clean work pieces without need for further handling or processing. For this purpose, it is desired to employ about 2 to 10% of the tetrasulfide condensation products previously described. Soluble cut ting oils are prepared by the addition of emulsihere such as sodium naphthenate, mahogany 1 in which the tetrasuliide is an alkyl xanthogen tetrasulilde.

3. A lubricating composition according to claim 1 in which the tetrasulflde is ethyl xanthyl tetrasulilde.

4. A lubricating composition according to claim i in which the mineral oil is an oil oi. high viscosity index. j

5. A cutting oil comprising a mineral lubricating oil and about 2 to% oia soluble xanthogen tetrasulfide having the probable structure:

where R and R are alkyl, cyclic or cyclo-alkyl groups, and the oxygen atoms may be replaced by sulfur.

soaps, rosin soaps, glycerol, alcohol and similar ingredients. 1 The lubricating oil base stocks are generally crude or refined mineral oils of about 70 viscosity at 100 F. (Saybolt) to about 5000 viscosity at 100 F.

In many cases, where antioxidant and anticorrosion effects are more desired, about 0.01 to 2% of the xanthate tetrasulildes is sumcient. For the preparation or E. P. greases and gear oils, higher viscosity base stocks may be employed, and there is often an advantage to employ stocks of high viscosity index, e. g. above 50. v

The present compositions may be employed i conjunction with linear polymer V. I. improvers, pour inhibitors, dyes, resins, voltolized'iats and/ or mineral oils or waxes, ester and other oiliness agents, phenolic or amino oxidation inhibitors, soaps, such as calcium stearate, lead oleate, lead naphthenate, aluminum naphthenate, and the like, dyes, halogenated compounds, such aschlorinated esters, chlorinated parailin waxes, etc., wetting agents, insecticides, germicides, fungicides, and the like.

The invention is not limited to any theory or structure or action, but islimited only by the 6. A composition of matter comprising any oil selected from the group consisting oi mineral oils and fatty oils, and a small amount of organic xanthogen tetrasulfide.

7. A lubricating composition comprising a lubricating oil base stock and at least about .01% of a soluble xanthogen sulfide having the general formula:

n-x-ti-(s)l-ii-x a where R and R are like or unlike alkyl, cyclic hydrocarbon, or mixed cyclo-alkyl radicals,'and X is either oxygen or sulfur.

8. The method of preparing improved lubrieating compositions which comprises reacting a compound having the general formula R--XH where R is an alkyl, cyclic hydrocarbon,-or mixed cyclo-alkyl radical and X is either oxygen or sulfur, with carbon disuliide and with a metal hydroxide to form a xanthate having the general formula:

I where M represents the nietal, then reacting 2 claims in which it is the intention to cover the s DISCLAIMER- mols or such xanthate in whichthe R constitu- -2,250,545ritual A. Mantra, Westfield, and' Eugene Lieber, Linden, N. .1. Lunaros'rma Courosrrrou. 'Patent dated July' 29, 1941. Disclaimer. filed 4 April 14, 1942, by the assignee, StandardOtl Development Company. Hereby enters this disclaimer to claims 1, 2, 3, 6, and 7.

[Oficial Gazette June 2, 1942.] 

